How do I know if I have Covid, flu, RSV or just a cold?

Certain lower respiratory symptoms demand you seek urgent medical care

How can I tell if I have influenza (flu), Covid, Respiratory Syncytial Virus (RSV) or the common cold?

The simple answer is that, very often, you won’t be able to tell which virus you have and you may even have several viruses at the same time.

“It’s nearly impossible to know which virus you have,” explains Dr Sam McConkey, consultant in infectious diseases at Beaumont Hospital, Dublin. “For example, SARS-CvC-2 [Covid] is mostly causing coughs, headaches and sore throats now, while in 2020, before we were all vaccinated, it was causing respiratory failure and pneumonia.”

The symptoms of all these highly contagious respiratory infections include headaches, coughs, runny/blocked noses, sore throats, fevers, chills, achy and sore muscles. Some people are also prone to vomiting and diarrhoea with respiratory infections.

So, should I get tested to see which virus I have?

There is no huge benefit in knowing which virus you have, according to Dr McConkey. “The Health Protection Surveillance Centre publish weekly data on notifiable infectious diseases (including Covid, Flu, RSV) gathered from a number of GPs throughout Ireland to monitor outbreaks. And people are tested in hospitals, so those with flu or Covid are put in single rooms or with others with the same virus but otherwise tests are unnecessary now.”


Experts in the USA have also noted that the self-administered antigen tests for Covid often don’t pick up the now most common JN.1 variant until day four or five, at which point, people are likely to have spread the virus to those close to them.

What’s the best way I can look after myself when I’m sick?

The usual advice applies to self-care for respiratory infections – drink plenty of fluids, take paracetamol-based medicines to bring down fever and reduce pain and rest. The HSE says that most viruses can be cared for at home and will usually clear between two to three weeks. (See for lots of good advice on self care).

Also, it’s important to stay at home from work, keep children at home from school and creches to prevent the spread of these viruses to vulnerable individuals.

How will I know when I should seek urgent medical treatment or advice?

Dr McConkey says there are certain lower respiratory symptoms that require urgent medical attention whether at a GP surgery, out-of-hours doctor services or at an Emergency Department. “If you experience uncontrollable shivering – called the rigours – in that your arms and legs are shaking and your teeth are chattering, you need prompt medical care because you are likely to have a deep-seated infection. Secondly, if you are coughing up yellow or green phlegm, you need a chest X-ray and antibiotics and thirdly, if you have shortness of breath so much that you can’t finish a sentence, you need to see a GP or go to an Emergency Room.”

How can I prevent catching another virus when I get better and how can I protect those close to me?

To protect yourself and others from respiratory viruses, you must follow all the so-called respiratory etiquette that we became so familiar with during the Covid pandemic. So, wash your hands regularly, sneeze into your elbow and wear a mask in crowded public spaces (eg on public transport, at busy indoor arts/sporting events).

If you have a chronic disease such as COPD (chronic obstructive pulmonary disease), asthma or you live with a young baby, a pregnant woman or a vulnerable older person, consider avoiding crowded indoor spaces for the next few weeks, after which the high levels of viral illnesses are expected to reduce somewhat.

The HSE also recommends that all eligible people keep up to date with Covid and flu vaccines. Older people living alone also need to be checked on more often if they have a viral illness as their symptoms can exacerbate very quickly.

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